A cytoarchitectonic study of the hypothalamus of the lizard,Calotes versicolor

Summary The hypothalamic nuclei of the lizard, Calotes versicolor, can be broadly divided into AF-positive and AF-negative. The AF-positive cell complexes include the nucleus supraopticus, nucleus paraventricularis, and a few interconnecting bridge cells. In addition, some AF-positive neurones are also observed in the median eminence. As many as 15 AF-negative nuclei-like accumulations of nerve cells can be identified in the hypothalamus. The nucleus periventricularis hypothalami of earlier authors is subdivided into eight circumscribed neuronal complexes. In addition, a few AF-negative nuclei, e.g. nucleus subfornicalis, nucleus ventralis tuberis, nucleus med. recessus infundibuli, nucleus lat. recessus infundibuli and nucleus praemamillaris, are regarded for the first time as anatomical entities. The distribution of the hypothalamic nuclei and their cytoarchitectonic features are described at the light microscopical level. An attempt has been made to interprete the nuclei identified in the present study on a comparative and phylogenetic basis.Dedicated to Professors W. Bargmann and B. Scharrer, the pioneers of neuroendocrinology, on the occasion of their birthday anniversariesSupported in part by research grant [No. F. 30-4 (6431)/76(SR-II)] by the University Grants Commission, New Delhi, India. The facilities provided by Dr. V. K. Thakare are hereby acknowledgedFormer scholar of the Alexander von Humboldt-Stuftung (1973–1975), Federal Republic of Germany. The present study was initiated by Professor A. Oksche, Department of Anatomy and Cytobiology, Justus Liebig University of GiessenThe facilities provided by Dr. A.K. Dorle are gratefully acknowledged

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Monoaminergic Systems in the Hypothalamus of the Acanthopterygian Chelon labrosus (Risso, 1826), with Special Reference to the Organon Vasculosum Hypothalami

Distribution of biogenic amines in the diencephalon of the advanced teleost Chelon labrosus was investigated by formaldehyde-induced fluorescence. We have found three closely interrelated bright yellow-green fluorescent monoaminergic cell groups having numerous cerebrospinal fluid-contacting cells with dendritic processes that protrude into the lumen of the third ventricle. The most rostral of them, the organon vasculosum hypothalami, located dorsally at the mid and caudal hypothalamus level, showed under electron microscopy some monoaminergic cells and others with an abundant smooth endoplasmic reticulum. The cerebrospinal fluid-contacting processes of both cell types, in association with numerous fibres, terminal buttons and some capillaries, constitute a thick and complex intraventricular mat. The other two fluorescent regions, nucleus recessi lateralis and nucleus recessi posterioris, border the lateral and posterior recesses of the hypothalamus. The ultrastructural characteristics of the organon vasculosum hypothalami and its intraventricular mat suggest a function in the regulation of chemical changes in the cerebrospinal fluid. These monoaminergic regions probably represent three cell masses originated from a single region in primitive fish.     

Localization of monoamines in the forebrain of two salmonid species,with special reference to the hypothalamo-hypophysial system

Summary In the salmon and trout aminergic cell bodies were found in the nucleus recessus lateraralis (NRL) and the nucleus recessus posterioris (NRP), both of which are situated near the third ventricle. Three cell types could be distinguished. Type 1 produces a green and type 2 a yellow fluorescence. The former type probably contains dopamine and the latter 5-hydroxytryptamine. Both types possess intraventricular protrusions in contact with the cerebrospinal fluid. The third cell type produces a less intense blue-green fluorescence; relatively few cells of this type have thick processes in contact with the ventricle. In addition, large fluorescent cells were found in the salmon, dorsal from the caudal part of the NRL. The various parts of the NRL and NRP are interconnected by thick bundles of nerve fibers; tracts leaving the nuclei could be traced for short distances only. The cells of the nucleus praeopticus (NPO), those of the medial part and to a much lesser extent also of the lateral part of the nucleus lateralis tuberis (NLT) have an aminergic innervation which probably originates from the NRL and/or NRP. All parts of the neurohypophysis contain many monoaminergic fibers, with aminergic material concentrated at the neuro-adenohypophysial interface. Fibers were not observed to penetrate the basal lamina. In the salmon and trout the fibers have a similar distribution, but differ in the intensity of fluorescence, being high in the salmon and low in the trout. Only in the trout have fluorescent cells been found in the adenohypophysis and very occasionally in the neurohypophysis. A number of these cells are basophilic and show a PAS-positive reaction.     

Fluorescence microscopy of neurons containing primary catecholamines in the ventral hypothalamus of the white-crowned sparrow,Zonotrichia leucophrys gambelii

Summary The ventral hypothalamus of White-crowned Sparrows, Zonotrichia leucophrys gambelii, was examined for primary catecholamines with the fluorescence technique of Falck-Hillarp and Owman. Photorefractory and photosensitive birds, photoperiodically stimulated and non-stimulated, were used.Four groups of catecholaminergic fibers were demonstrated: (1) afferent fibers of extra-hypothalamic origin to the infundibular nucleus where there are extensive synaptic contacts with non-fluorescent perikarya; (2) fibers apparently extending ventrally from an area with fluorescent perikarya in the vicinity of the paraventricular organ to the infundibular nucleus via the stratum cellulare internum and lateral pathways; (3) afferent fibers to the subependymal layer of the median eminence; and (4) afferent fibers to the zona externa of the median eminence. Fluorescent fibers that pass transversely through the median eminence may be derived from any of the last three categories. It appears that the fibers of the zona externa (4) are not derived to any appreciable extent from those of the subependymal layer (3). Because fluorescent perikarya could not be demonstrated in the infundibular nucleus no conclusion can be reached with respect to this nucleus as an origin for fibers (3) and (4).Diurnal cycles in the number of fluorescent terminals observable and in the intensity of the fluorescence in the palisade layer in photosensitive birds subjected to different photoperiodic regimes, in castrates, and in photorefractory birds are described tentatively on the basis of subjective assessments. Some possible implications of the differences are discussed.This communication is based extensively on a thesis, Primary catecholamine fibers in the ventral hypothalamus of the White-crowned Sparrow, Zonotrichia leucophrys gambelii, submitted in partial fulfillment of the requirements for the degree of Master of Science, University of Washington, August 1968, by the senior author. The research on which it is based was supported extensively by Grant No. NB 06187 from the National Institutes of Health to Professor Donald S. Farner. We are grateful to Ciba Pharmaceutical Products, Inc. for a supply of Serpasil.     

Cytoarchitectonic pattern of the hypothalamus in the crocodile,Gavialis gangeticus

Summary The hypothalamus of the crocodile, Gavialis gangeticus, was investigated to reveal the organization of various nuclear complexes and to suggest homologies. The hypothalamic nuclei of G. gangeticus are composed of magnocellular and parvocellular neuronal entities. In the magnocellular system the nucleus supraopticus is well developed, whereas the nucleus paraventricularis and nucleus retrochiasmaticus are represented by scattered somata. Application of cytoarchitectonic criteria permits the delineation of 24 distinct parvocellular nuclear complexes extending rostrocaudally from the anterior commissure to the level indicated by the median eminence and nucleus mamillaris; some are further divisible into subgroups. The nucleus of the preoptic recess appears to be a unique property of the crocodilian hypothalamus. The nucleus suprachiasmaticus possesses a wing-like ventrolateral expansion that protrudes along the lateral aspect of the optic nerve. The tuberal region displays an elaborate pattern of nuclei segregated by regional specializations of the neuropil. The nucleus hypothalamicus posterior occupies the periventricular zone, flanked laterally by the nucleus hypothalamicus dorsomedialis and nucleus arcuatus. Further laterally, extended subdivisions of the nucleus hypothalamicus lateralis contain neurons rich in Nissl substance; the specializations shown by these subdivisions, in comparison to the lateral cell groups in lizards and snakes, are suggestive of enhanced integrative functions. The conspicuous paraventricular organ is encircled by dorsal and ventral divisions of the nucleus of the paraventricular organ. The neurons of the nucleus subfornicalis and nucleus hypothalamicus medialis are few in number, but large in size. The general organization of the hypothalamus of G. gangeticus reveals a mosaic-like pattern with the constituent groups appearing as clusters of small and large neurons, arranged medially and laterally in a definitive manner and accompanied by extensive zones of neuropil in the subependymal and lateral zones of the hypothalamus. The median eminence is divisible into an anterior and a posterior region. The nuclear pattern in the crocodilian hypothalamus reveals a higher state of morphologic organization compared to the situation in lizards or snakes, and thus reflects an evolutionary trend in the avian direction.     

The sensory innervation of the pineal organ in the lizard,Lacerta viridis,with remarks on its position in the trend of pineal phylogenetic structural and functional evolution

Summary The sensory innervation of the pineal organ of adult Lacerta viridis has been investigated. Some specimens of Lacerta muralis lillfordi were also used. In the pineal epithelium, a small number of nerve cell pericarya of a sensory type are present. They lie either solitary or in small clusters close to the basement membrane. The axons originating from the nerve cell bodies, i. e. the pineal sensory nerve fibers, first course in the intraepithelial nerve fiber layer which is only locally present and contains a restricted number of unmyelinated fibers. In Lacerta viridis, the pineal fibers generally leave the epithelium at the proximal part of the organ proper. They then form small bundles which run along the outer surface of the basement membrane in the leptomeningeal connective tissue covering. At the proximal end of the pineal stalk the single bundles assemble constituting the pineal nerve. In Lacerta muralis the fibers leave the pineal epithelium at the proximal end of the stalk running farther down within the epithelium. Many fibers become myelinated after leaving the pineal epithelium. The pineal nerve runs ventralward in the midplane just caudal to the habenular commissure to which no fibers are given off. Continuing their ventralward course between the habenular commissure and the rostral end of the posterior commissure which is traversed by some of them, the pineal fibers reach the dorsal border of the subcommissural organ. Small separate aberrant pineal bundles traverse the posterior commissure at various more caudal levels. Having reached the dorsal border of the subcommissural organ, part of the pineal fibers continue their ventralward course directly running along the lateral sides of this organ to reach the periventricular nerve fiber layer lateral and ventral to it. A restricted number of fibers first turns in a caudal direction running between the base of the posterior commissure and the base of the subcommissural organ before turning ventralward to reach the periventricular layer. Most probably, pineal fibers do neither join the posterior commissural system nor innervate the subcommissural organ. Once having reached the periventricular layer, some pineal fibers curve in a rostral direction while others, before doing so, send a collateral in a caudal direction. Both, the main fibers and the collaterals, contribute to the formation of the periventricular layer. The sites of termination of the pineal fibers could not be ascertained.From the presence of intraepithelial sensory nerve cell bodies and from literature data on the ultrastructure of pineal neurosensory cells it is concluded that the adult pineal organ of Lacerta has a, although rudimentary, (photo)sensory function. The demonstration by our guest-worker Dr. W. B. Quay, of the intraepithelial presence of a tryptamine compound, probably serotonin, points, moreover, to a secretory function of this organ.In adult Lacerta a well-developed parietal nerve connects the parietal eye with the left lateral habenular nucleus. It traverses the habenular commissure.In gratitude and with admiration this paper is dedicated to Prof. Berta Scharrer and to the memory of Prof. Ernst Scharrer.     

5-Hydroxytryptamin im Gehirn der Eidechse (Lacerta viridis und Lacerta muralis)

Zusammenfassung Mit Hilfe der Methode von Falck und Hillarp wurde die Verteilung von 5-Hydroxytryptamin im Zentralnervensystem von Lacerta viridis und muralis untersucht. Mikrospektrometrische Analysen zeigen, daß sich die Gelbfluoreszenz wie formaldehyd-kondensiertes 5-Hydroxytryptamin verhält; chemische Bestimmungen ergeben hohe Werte von 5-Hydroxytryptamin im Gehirn der Eidechsen (5,2–6,4 g/g). Kerngebiete des Zwischen-, Mittel und Vorderhirns, die überwiegend in somatosensible oder sensorische Bahnen eingeschaltet sind, werden von Endaufsplitterungen 5-hydroxytryptaminhaltiger Neurone erreicht. Es wird angenommen, daß das Ursprungsgebiet dieser Fasersysteme im Tegmentum liegt. Der Nucleus reticularis mesencephali enthält zahlreiche Nervenzellen, deren Perikaryen einen hohen Gehalt an 5-Hydroxytryptamin aufweisen.

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5-Hydroxytryptamine in the brain of Lacerta viridis and Lacerta muralis

Summary The distribution of 5-hydroxytryptamine in the central nervous system of the lizards Lacerta viridis and muralis was investigated with the fluorescence method of Falck and Hillarp. Microspectrometric analyses revealed that the yellow fluorescence had the characteristics of the fluorophore of 5-hydroxytryptamine and chemical determinations on whole brains demonstrated the presence of considerable quantities of 5-hydroxytryptamine (5,2–6,4 g/g). Nuclear areas of the mesencephalon, di and telencephalon, which are mainly intercalated in sensory pathways, receive terminal ramifications of 5-hydroxytryptaminecontaining neurons. These fibres are presumed to originate from cells situated in the tegmentum. The nucleus reticularis mesencephali is shown to contain numerous perikarya of nerve cells rich in 5-hydroxytryptamine.

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Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft und die Joachim Jungius-Gesellschaft zur Förderung der Wissenschaften, Hamburg.

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Supported by grants from the Swedish Natural Science Research Council/project no. 99-35, and the Swedish Medical Research Council/project no. B 68-12x-712-03B.     

Monoamine oxidase in the hypothalamo-hypophysial region of the teleosts,Anguilla japonica and Oryzias latipes

Summary Distribution of monoamine oxidase (MAO) was histochemically examined in the hypothalamo-hypophysial region of the eel (Anguilla japonica) and the medaka (Oryzias latipes) with a modified Glenner's tryptamine-tetrazolium method. The hypothalamic neurosecretory cells showed very weak MAO activity in their perikarya. MAO-positive fibers were present in close contact with the neurosecretory cells, suggesting that monoaminergic fibers participate in the control of neurosecretory cell activity. The nucleus lateralis tuberis (NLT) contained cells exhibiting strong MAO activity. These cells must be monoaminergic neurons.In the anterior region of the neurohypophysis of both eel and medaka, two bundles of MAO-positive fibers originating from the NLT proceed down along each side of the third ventricle into the pars distalis. This suggests that monoaminergic neurons of the NLT are involved in the release of hormones from the pars distalis. In addition to these tracts, numerous MAO-positive fibers proceed backward from the post-optic area and end around the blood capillaries located between the neurohypophysis and the pars intermedia in both species.I wish to express my gratitude to Prof. H. Kobayashi for his valuable advice during the course of this study. I am indebted to Prof. S. Uchida, Ocean Research Institute, University of Tokyo, for supplying the eels.     

Monoamine fluorescence in the median eminence of the Japanese quail,Coturnix coturnix japonica,following medial basal hypothalamic deafferentation

Summary Monoamine fluorescence was examined in the ventral hypothalamus of the Japanese quail, Coturnix coturnix japonica after medial basal hypothalamic deafferentation. In sham-operated control birds, numerous yellow-green fluorescent fibers were observed in the median eminence and the nucleus tuberis. In the area of the paraventricular organ, a number of fluorescent fibers and cell bodies were observed. In birds with deafferented hypothalami, fluorescence disappeared both in the median eminence and the nucleus tuberis. In the area of the paraventricular organ, which was within the area of deafferentation, fluorescence of neuronal perikarya did not change, but fluorescent fibers decreased markedly in number. Disappearance of monoamine fluorescence in the median eminence and the nucleus tuberis is discussed in relation to the tanycyte absorptive function and gonadal development.Supported by Grants from the Ministry of Education to Professors T. Bando and H. Kobayashi, and a Grant from the Ford Foundation to Prof. H. Kobayashi.     

Immunocytochemical localization of neurotensin-containing neurons in the hypothalamus of the japanese quail,Coturnix coturnix japonica

Summary The hypothalamus of Japanese quail, Coturnix coturnix japonica, has been studied by means of the peroxidase-antiperoxidase immunocytochemical method, with the use of antibodies to synthetic neurotensin (NT). A number of immunoreactive neuronal perikarya occur in the medial preoptic nucleus of the rostral hypothalamus and a few in the accessory part of paraventricular nucleus and dorsal portion of the infundibular nucleus. Some of them correspond to the parvocellular neurons previously identified tentatively as neurosecretory (Mikami et al. 1975, 1976). Large numbers of immunoreactive neuronal fibers are found in the preoptic area, which extend as a remarkable fiber tract from this area to the ventral septal area and to the subfornical organ. A few immunoreactive fibers also extend ventrocaudally to the infundibular nucleus and to the neural lobe.This investigation was supported by Scientific Research Grants No. 556196 and No. 576176 from the Ministry of Education of Japan to Professor Mikami and Mr. Yamada     

Distribution of monoamines in the diencephalon and pituitary of the dogfish,Scyliorhinus canicula L.

Summary The distribution of monoamines in the diencephalon and pituitary of the dogfish, Scyliorhinus canicula, has been investigated using the histochemical fluorescence technique of Falck and Hillarp (Falck and Owman, 1965). Terminals of monoamine-containing axons were found in the neurointermediate lobe of the pituitary and the axons were traced, by means of nialamide and L-dopa treatment and lesions, to the nucleus medius hypothalamicus. A separate hypothalamic system converging on the anterior median eminence and the occurrence of aminergic cells in the nuclei lobi inferiores and nucleus medius hypothalamicus were similarly demonstrated. Normal fish show a bilateral uncrossed tegmental tract and two areas of catecholamine-containing neurones in modified ependymal organs. The organum vasculosum hypothalami includes both primary catecholamine and 5-hydroxytryptamine-containing cell types whilst the organum vasculosum praeopticum has only the former type. Both organs contain cells which send club-like processes into the third ventricle. The subcommissural organ does not contain monoamines.The role of hypothalamic catecholamine systems in the regulation of pituitary function is discussed.     

Development of melanin-concentrating hormone-immunoreactive elements in the brain of gilthead seabream (Sparus auratus)

The development of the hypothalamic melanin-concentrating hormone (MCH) system of the teleost Sparus auratus has been studied by immunocytochemistry using an anti-salmon MCH serum. Immunoreactive perikarya and fibers are found in embryos, larvae, and juvenile specimens. In juveniles, most labeled neurons are present in the nucleus lateralis tuberis; some are dispersed in the nucleus recessus lateralis and nucleus periventricularis posterior. From the nucleus lateralis tuberis, MCH neurons project a conspicuous tract of fibers to the ventral hypothalamus; this penetrates the pituitary stalk and reaches the neurohypophysis. Most fibers end close to the cells of the pars intermedia, and some reach the adenohypophysial rostral pars distalis. Immunoreactive fibers can also be seen in extrahypophysial localizations, such as the preoptic region and the nucleus sacci vasculosi. In embryos, MCH-immunoreactive neurons first appear at 36 h post-fertilization in the ventrolateral margin of the developing hypothalamus. In larvae, at 4 days post-hatching, perikarya can be observed in the ventrolateral border of the hypothalamus and in the mid-hypothalamus, near the ventricle. At 26 days post-hatching, MCH perikarya are restricted to the nucleus lateralis tuberis. The neurohypophysis possesses MCH-immunoreactive fibers from the second day post-hatching. The results indicate that MCH plays a role in larval development with respect to skin melanophores and cells that secrete melanocyte-stimulating hormone. Received: 4 April 1995 / Accepted: 17 July 1995     

A phylogenomic resolution for the taxonomy of Aegean green lizards

Lacerta pamphylica and Lacerta trilineata are two currently recognized green lizard species with a historically problematic taxonomy. In cases of tangled phylogenies, next-generation sequencing and double-digest restriction-site-associated DNA protocols can provide a wealth of genomic data and resolve difficult taxonomic issues. Here, we generated genome-wide SNPs and mitochondrial sequences, and applied molecular species delimitation approaches to provide a stable taxonomy for the Aegean green lizards. Mitochondrial gene trees, genetic cluster delimitation and population structure analyses converged into recognizing the populations of (a) L. pamphylica, (b) east Aegean islands, Anatolia and Thrace (diplochondrodes lineage), (c) central Aegean islands (citrovittata), and (d) remaining Balkan populations and islands (trilineata), as separate clusters. Phylogenomic analyses revealed a split into two major clades, east and west of the Aegean Barrier, unambiguously showing a sister–clade relationship between pamphylica and diplochondrodes, rendering L. trilineata paraphyletic. Species delimitation models were tested in a Bayesian framework using the genomic SNPs: lumping all populations into a single ‘species’ had the lowest likelihood but the current taxonomy was also outperformed by all other models. All lines of evidence support the Pamphylian green lizard as a valid species; thus, east Aegean L. trilineata should also be considered a distinct species under the name Lacerta diplochondrodes. Finally, evidence from the mitochondrial and nuclear genomes is overwhelmingly in favour of recognizing the morphologically distinct Cycladian green lizards as a distinct species. We propose their elevation to full species under the name Lacerta citrovittata. All remaining insular and continental populations of the Balkan Peninsula represent the species L. trilineata.     

Microsatellite markers developed for a Swedish population of sand lizard (<Emphasis Type="Italic">Lacerta agilis</Emphasis>)

Populations of sand lizards (Lacerta agilis) are declining throughout its north-western range. Here we characterize fifteen new microsatellite markers developed specifically for parentage analysis in a small Swedish population of sand lizards. These loci were screened in the Asketunnan population and a much larger and genetically diverse Hungarian population, with heterozygosities ranging from (0.217–0.875) and (0.400–0.974), respectively. All loci were in Hardy-Weinberg Equilibrium in the Swedish population but eight loci had significant heterozygote deficiencies in the Hungarian population. Two loci were significantly linked in both populations. These microsatellite loci are likely to be applicable in research on other sand lizard populations throughout Europe. An erratum to this article can be found at     

Unterschiedlicher elektronenmikroskopischer Feinbau der Sinneszellen im Parietalauge und im Pinealorgan (Epiphysis cerebri) der Lacertilia

Zusammenfassung Das Parietalauge und das Pinealorgan (Epiphysis cerebri) der Echsen Lacerta sicula campestris, Lacerta vivipara, Lacerta agilis, Anguis fragilis und Iguana iguana wurden elektronenmikroskopisch untersucht und die Ultrastrukturen ihrer Rezeptoren verglichen. Die langen Außenglieder des Parietalauges sind aus regulären scheibenförmigen Lamellenverbänden aufgebaut. Im Pinealorgan der Echsen findet man zwar eine gewisse Anzahl von kurzen regulär gebauten Außengliedern, im Vordergrund stehen aber die zahlreichen alterierten und degenerierten Außengliedstrukturen. Diese sind durch Auflösung des charakteristischen Lamellenverbandes, die offenbar zur Bildung von Tubuli oder Bläschen führt, konzentrische Lamellenkörper und membranbegrenzte Vakuolen verschiedenen Inhalts gekennzeichnet. Außerdem wurden noch rudimentäre oder unreife (Neubildung ?) Außengliedformen beobachtet. Aufmerksamkeit verdienen einige artspezifische und ontogenetische Unterschiede. Parenchymzellen der Lacertilierepiphyse (1. epitheliale, lumennahe Elemente, die sich offenbar von Sinneszellen herleiten, 2. verzweigte Formen der tieferen Wandschichten) und marklose Nervenfasern enthalten verschiedene Typen elektronendichter Granula. Das Epiphysenproblem wird auf der Basis dieser Befunde und der elektrophysiologischen Ergebnisse von Dodt u. Mitarb. diskutiert.

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Differences in the ultrastructure of the sensory cells in the parietal eye and the pineal organ (epiphysis cerebri) of lacertiliaA contribution to the pineal problem

Summary The parietal eye and the pineal organ (epiphysis cerebri) of the lizards, Lacerta sicula campestris, Lacerta vivipara, Lacerta agilis, Anguis fragilis and Iguana iguana, have been studied by means of electron microscopy. The ultrastructure of the parietal eye and pineal receptor cells is compared. The long outer segments of the parietal eye appear normal and show regular stacks of discs. In the pineal organ some of the short outer segments are essentially normal, but there are many disorganized and degenerated outer segment structures. Separation of discs and transformation into tubules and vesicles, whorllike structures or membrane-bounded and vesicle-filled compartments are very abundant. In addition, some rudimentary or anlage-like (renewal ?) forms of the outer segment were observed. Attention should be given to some interspecific and ontogenetic differences. Different types of dense-core vesicles were found in (1) the epithelial and pinealocyte-like parenchymal cells and (2) the unmyelinated nerve fibers of the lacertilian pineal organs. The pineal problem is discussed in view of these findings and the electrophysiological results of Dodt et al.

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Herrn Prof. Dr. Dr. h. c. W. E. Ankel gewidmet.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Innervation of the testicular interstitial tissue in reptiles

Summary In the tortoise Testudo graeca, the lizards Lacerta dugesi and Lacerta pityusensis, and the snake Natrix natrix, the innervation of the testicular interstitial tissue was studied by light and electron microscopy, the acetylcholinesterase (ache) technique, the Falck-Hillarp method for the detection of catecholamines, and the application of 6-hydroxydopamine. The intertubular spaces of the reptilian testes studied contain adrenergic nerve fibers the amount and distribution of which varies considerably both in various species and in various stages of the reproduction cycle. Nerve fibers do not enter the seminiferous epithelium. Fluorescence microscopy of the lizard testis reveals catecholaminergic varicosities which are mainly arranged around blood vessels, but do not show obvious connexions to Leydig cells. Ache-positive fibers are equally distributed in lizard testes surrounding each seminiferous tubule. In Natrix natrix ache-positive fibers are irregularly spread among groups of tubules, without showing a definite relation to Leydig cells either. By electron microscopy bundles of unmyelinated axons and axon terminals can be more easily detected in the testes of immature animals than in adult. Terminals of nerve fibers containing small (400–500 Å in diameter) and large (800–1400 Å) dense-cored vesicles and sometimes small clear vesicles establish contacts with Leydig cells. Three types of contact are described. 1. Contacts par distance at a distance of about 2000 Å and basal lamina interposed; 2. membranous contacts having a 200 Å gap only between axolemma and Leydig cell plasmalemma; 3. invaginations of terminals into Leydig cell perikarya. The latter may exhibit surface specialisations, which strongly resemble postsynaptic membrane thickenings. Experiments using 6-hydroxydopamine underline the adrenergic character of testicular nerve fibers, which can be regarded as another example of non-cholinergic, ache-positive neurons. In the testis of the immature tortoise profiles of axons occur which probably represent purinergic, ache-positive neurons.Supported by a grant from the Deutsche Forschungsgemeinschaft (Un 34/1).I am much indebted to Mrs. R. Sprang for her skillfull technical assistance.     

Immunocytochemical distribution of FMRFamide-like substance in the brain of the cloudy dogfish,Scyliorhinus torazame

Summary The distribution of the molluscan cardioexcitatory tetrapeptide FMRFamide (Phe-Met-Arg-Phe-NH₂) in the brain of the cloudy dogfish, Scyliorhinus torazame, was examined by immunocytochemistry. FMRFamide-like immunoreactivity was demonstrated to occur extensively in various regions of the dogfish brain, except for the corpus cerebelli. Immunoreactive neuronal perikarya were located in the ganglion of the nervus terminalis, the preoptic area, and the hypothalamic periventricular gray matter consisting of the nucleus medius hypothalamicus, the nucleus lateralis tuberis, and the nucleus lobi lateralis. some of the immunoreactive cells in the hypothalamus were identified as cerebrospinal fluid-contacting neurons. The bulk of the immunostained fibers in the nervus terminalis penetrated into the midventral portion of the telencephalon and ran dorsocaudally toward the basal telencephalon and hypothalamus, showing radial projections or ramifications. The labeled fibers were abundant in the midbasal part of the telencephalon and in the hypothalamus, where some fibers were found in loose networks around the cell bodies of the nucleus septi and hypothalamic periventricular nuclei. The fibers demonstrated in the hypothalamus terminated around the vascular wall of the primary capillary plexus of the median eminence or penetrated deeply into the pars intermedia of the hypophysis. These results suggest that, in the dogfish, an FMRFamide-like substance participates in the regulation of adenohypophysial function. This molecule may have a role as a neurotransmitter and/or neuromodulator in the central nervous system.     

Nervous connections of the parietal eye in adult Lacerta s. sicula Rafinesque as demonstrated by anterograde and retrograde transport of horseradish peroxidase

Summary Subsequent to the injection of horseradish peroxidase into the parietal eye of adult Lacerta sicula, the course of the parietal nerve and its projections were determined.The parietal nerve enters the left habenular ganglion where it branches into a medial and a lateral route. Some nerve fibers decussate within the habenular commissure. Whereas this pathway exhibits a striking asymmetry at the level of the habenular ganglia, its projections to the dorsolateral nucleus of the thalamus, the periventricular hypothalamic area, the preoptic hypothalamic and telencephalic regions, and the pretectal area are arranged in a strictly symmetric manner. A possible innervation of tegmental areas could not be proven due to the presence of endogenous peroxidase within these regions. No parietal nerve fibers were observed in the optic tectum.In a few animals investigated, scattered labeled perikarya were located in the periventricular hypothalamic gray indicating a parietopetal innervation in Lacerta sicula. The injection of horseradish peroxidase into one of the lateral eyes revealed terminal areas of the optic nerve within the preoptic region, and the thalamic and pretectal nuclei, displaying partial overlapping with the projections of the parietal nerve to these areas.From the present investigation further evidence is obtained that the pineal complex of lower vertebrates is a component of the photoneuroendocrine system. Particular emphasis is placed upon the nervous connections between the parietal eye and the hypothalamus, described for the first time in the present study.Supported by the Deutsche Forschungsgemeinschaft (Grant Ko 758/1)In partial fulfillment of the requirements of the degree of Dr. med., Faculty of Medicine, Justus Liebig University of Giessen     

Distribution of catecholaminergic and serotoninergic systems in forebrain and midbrain of the newt,Triturus alpestris (Urodela)

Summary Mapping of monoaminergic systems in the brain of the newt Triturus alpestris was achieved with antisera against (1) thyrosine hydroxylase (TH), (2) formaldehyde-conjugated dopamine (DA), and (3) formaldehyde-conjugated serotonin (5-HT). In the telencephalon, the striatum was densely innervated by a large number of 5-HT-, DA-and TH-immunoreactive (IR) fibers; IR fibers were more scattered in the amygdala, the medial and lateral forebrain bundles, and the anterior commissure. In the anterior and medial diencephalon, TH-IR perikarya contacting the cerebrospinal fluid (CSF-C perikarya) were located in the preoptic recess organ (PRO), the organum vasculosum laminae terminalis and the suprachiasmatic nucleus. Numerous TH-IR perikarya, not contacting the CSF, were present in the posterior preoptic nucleus and the ventral thalamus. At this level, DA-IR CSF-C neurons were only located in the PRO. In the posterior diencephalon, large populations of 5-HT-IR and DA-IR CSF-C perikarya were found in the paraventricular organ (PVO) and the nucleus infundibularis dorsalis (NID); the dorsal part of the NID additionally presented TH-IR CSF-C perikarya. Most regions of the diencephalon showed an intense monoaminergic innervation. In addition, numerous TH-IR, DA-IR and 5-HT-IR fibers, orginating from the anterior and posterior hypothalamic nuclei, extended ventrally and reached the median eminence and the pars intermedia of the pituitary gland. In the midbrain, TH-IR perikarya were located dorsally in the pretectal area. Ventrally, a large group of TH-IR cell bodies and some weakly stained DA-IR and 5-HT-IR neurons were observed in the posterior tuberculum. No dopaminergic system equivalent to the substantia nigra was revealed. The possible significance of the differences in the distribution of TH-IR and DA-IR neurons is discussed, with special reference to the CSF-C neurons.Abbreviations AM amygdala - CAnt commissura anterior - CH commissura hippocampi - CP commissura posterior - Ctm commissura tecti mesencephali - DH dorsal hypothalamus - DTh dorsal thalamus - FLM fasciculus longitudinalis medialis - Fsol fasciculus solitarius - H habenula - LFB lateral forebrain bundle - ME median eminence - MFB medial forebrain bundle - NID nucleus infundibularis dorsalis - nIP neuropil of nucleus interpeduncularis - NPOP nucleus preopticus posterior - NS nucleus septi - OVLT organum vasculosum laminae terminalis - PD pars distalis - Pdo dorsal pallium - PHi primordium hippocampi - PI pars intermedia - Pl lateral pallium - PN pars nervosa - PRO preoptic recess organ - Ptec pretectal area - PVO paraventricular organ - Ra nucleus raphe - Rm nucleus reticularis medius - SCO subcommisural organ - ST striatum; strm stria medullaris thalami - strt stria terminalis thalami - TM tegmentum mesencephali - TO tectum opticum - TP tuberculum posterius - trch tractus cortico-habenularis - trmp tractus mamillopeduncularis - VH ventral hypothalamus - Vm nucleus motorius nervi trigemini - VTh ventral thalamus - II optic nerve     

Ultrastructural study of the epithelial mucous cells in lizards (Lacertilia)

Summary An ultrastructural study of the mucous cells of the intestinal epithelium of four lacertilian species (Lacerta lepida, Lacerta hispanica, Psammodromus algirus and Acanthodactylus erythrurus) is here reported. Two types of mucous cells have been found in these species: common mucous cells and granular mucous cells. Immature and mature forms of both types have been observed. The common mucous cells or typical goblet cells have the same characteristics in all four species. The granules of the granular mucous cells of the two species of Lacerta are similar but differ from those of the other two species.